Archive for August 2012
Top 10 Linux Virtualization Software
Top 10 Linux Virtualization Software
Virtualization is the latest buzz word.
You may wonder computers are getting cheaper every day, why should I
care and why should I use virtualization? Virtualization is a broad term
that refers to the abstraction of computer resources such as:
- Platform Virtualization
- Resource Virtualization
- Storage Virtualization
- Network Virtualization
- Desktop Virtualization
Why should I use virtualization?
- Consolidation - It means combining multiple software workloads on one computer system. You can run various virtual machines in order to save money and power (electricity).
- Testing - You can test various configuration. You can create less resource hungry and low priority virtual machines (VM). Often, I test new Linux distro inside VM. This is also good for students who wish to learn new operating systems and programming languages / database without making any changes to working environment. At my work place I give developers virtual test machines for testing and debugging their software.
- Security and Isolation - If mail server or any other app gets cracked, only that VM will be under control of the attacker. Also, isolation means misbehaving apps (e.g. memory leaks) cannot bring down whole server.
Open Source Linux Virtualization Software
- OpenVZ is an operating system-level virtualization technology based on the Linux kernel and operating system.
- Xen is a virtual machine monitor for 32 / 64 bit Intel / AMD (IA 64) and PowerPC 970 architectures. It allows several guest operating systems to be executed on the same computer hardware concurrently. XEN is included with most popular Linux distributions such as Debian, Ubuntu, CentOS, RHEL, Fedora and many others.
- Kernel-based Virtual Machine (KVM) is a Linux kernel virtualization infrastructure. KVM currently supports native virtualization using Intel VT or AMD-V. A wide variety of guest operating systems work with KVM, including many flavours of Linux, BSD, Solaris, and Windows etc. KVM is included with Debian, OpenSuse and other Linux distributions.
- Linux-VServer is a virtual private server implementation done by adding operating system-level virtualization capabilities to the Linux kernel.
- VirtualBox is an x86 virtualization software package, developed by Sun Microsystems as part of its Sun xVM virtualization platform. Supported host operating systems include Linux, Mac OS X, OS/2 Warp, Windows XP or Vista, and Solaris, while supported guest operating systems include FreeBSD, Linux, OpenBSD, OS/2 Warp, Windows and Solaris.
- Bochs is a portable x86 and AMD64 PC emulator and debugger. Many guest operating systems can be run using the emulator including DOS, several versions of Microsoft Windows, BSDs, Linux, AmigaOS, Rhapsody and MorphOS. Bochs can run on many host operating systems, like Windows, Windows Mobile, Linux and Mac OS X.
- User Mode Linux (UML) was the first virtualization technology for Linux. User-mode Linux is generally considered to have lower performance than some competing technologies, such as Xen and OpenVZ. Future work in adding support for x86 virtualization to UML may reduce this disadvantage.
Proprietary Linux Virtualization Software
- VMware ESX Server and VMWare Server - VMware Server (also known as GSX Server) is an entry-level server virtualization software. VMware ESX Server is an enterprise-level virtualization product providing data center virtualization. It can run various guest operating systems such as FreeBSD, Linux, Solaris, Windows and others.
- Commercial implementations of XEN available with various features and support.
- Citrix XenServer : XenServer is based on the open source Xen hypervisor, an exceptionally lean technology that delivers low overhead and near-native performance.
- Oracle VM : Oracle VM is based on the open-source Xen hypervisor technology, supports both Windows and Linux guests and includes an integrated Web browser based management console. Oracle VM features fully tested and certified Oracle Applications stack in an enterprise virtualization environment.
- Sun xVM : The xVM Server uses a bare-metal hypervisor based on the open source Xen under a Solaris environment on x86-64 systems. On SPARC systems, xVM is based on Sun's Logical Domains and Solaris. Sun plans to support Microsoft Windows (on x86-64 systems only), Linux, and Solaris as guest operating systems.
- Parallels Virtuozzo Containers - It is an operating system-level virtualization product designed for large-scale homegenous server environments and data centers. Parallels Virtuozzo Containers is compatible with x86, x86-64 and IA-64 platforms. You can run various Linux distributions inside Parallels Virtuozzo Containers.
Tag :
Linux
4 Steps to Protect Your Data in The Cloud
I have been quite surprised in recent months at how many individuals and companies store content in the cloud without thinking about who might have access to their data and how these files are being used. There seems to be an implicit trust. After all, backing up data to the cloud is more reliable and recoverable than backing up to onsite hard drives.
Common sense mandates that you should do due diligence before storing data in the cloud. This article provides you with a four step roadmap to guide you through the process of assessing your cloud storage provider’s security policies.
1. Read the Fine Print
We are all guilty of scrolling through terms and conditions on web sites and pressing the agree button without actually reading anything. Even though we have all heard horror stories about people who failed to read the small print, we either perceive that it is not worth spending time on or think that we will not be able to interpret it correctly.
“By submitting or posting such
Content ….. you grant Apple a worldwide, royalty-free, non-exclusive
license to use, distribute, reproduce, modify, adapt, publish,
translate, publicly perform and publicly display such Content on the
Service solely for the purpose for which such Content was submitted or
made available, without any compensation or obligation to you.”
The first step to protecting your data is to take the time to read the small print and assess the risk to your content. If the terms are not clear or you determine that they put your data at risk, then you need to look for another storage service provider.
2. Find Out Where Your Data is Being Kept
Many cloud storage providers have data centers located all around the world. The good news is that placing data centers overseas can provide redundancy and keep the cost of storage low. The bad news is that your data is subject to the regulation of the country and the state that it is stored in.
For example, suppose the storage provider data center is hacked and there is a risk that your data has been compromised. Depending on the country and state your data is stored in, your storage service provider may or may not be legally obligated to send you notification of the theft. Similarly, if the in-country law enforcement may issue the service provider with a warrant to view your data, the storage service provider is not obligated to notify the data owner that their data is subject to a legal investigation.
"When you upload or otherwise submit
content to our Services, you give Google (and those we work with) a
worldwide license to use, host, store, reproduce, modify, create
derivative works (such as those resulting from translations, adaptations
or other changes we make so that your content works better with our
Services), communicate, publish, publicly perform, publicly display and
distribute such content."
3. Determine if Your Videos and Images are Being Compressed
If you are storing pictures or videos in the cloud, you may be surprised to find that the storage service provider will compress them. You will therefore never be able to regain the original quality. Depending on your planned usage for your content this may be or may not be a problem.
“Apple may transmit your Content
across various public networks, in various media, and modify or change
your Content to comply with technical requirements of connecting
networks or devices or computers.”
4. Encrypt, Encrypt, Encrypt
Many storage service providers encrypt your data while you are transferring your data between your computer and the cloud, but then store your data in plain text. This protects your data while it is being sent over the public Internet, but it is not protected against possible breached in security at the data center. Extract from Federal Trade Commission investigation last year:
“The choice of encryption algorithms
is an important component in the security of a system. However, equally
important is the storage and management of the keys used to encrypt
data. The keys used to encrypt users’ data are know some Dropbox
employees and stored on the company’s server.”
Tag :
Cloud
IPv6 Address Types
Overview
With the coming wide scale implementation of IPv6, it has become vital that network engineers become familiar with IPv6 and how it operates. While there are many different parts of IPv6 that mimic the same behaviors of IPv4, there are some subtle changes that engineers must be aware of. This article takes a look at the IPv6 address types and how they compare with the existing IPv4 address types.IPv6 Address Types
Like IPv4, IPv6 has three different address types that are commonly used; these include:- Unicast
- Multicast
- Anycast
Unicast
The IPv6 unicast address type operates in the same way as IPv4; a unicast address is used to send traffic from one source device to one destination device. This is the most used address type as most traffic (currently) is sourced from one place and destined for one other place; this may change as network telephone and video services become used more.Multicast
The IPv6 multicast address type also operates in the same was as with IPv4; a multicast address is used to send traffic to a group of devices. This is used when there is a single source that needs to send traffic to multiple destinations; this traffic can be treated differently by the intermediate devices compared with unicast. If this same traffic would be sent via unicast methods, these devices would need to process each traffic stream from source to destination separately causing additional traffic delay.Another large difference between IPv4 and IPv6 is with the IPv4 broadcast address type. IPv4 utilized a broadcast address type that allowed devices the ability to send a single packet that would then be delivered to all devices on the local subnet. While this capability was very useful, it would also cause all devices on the local subnet to process the packet. This was not a problem when the device was the anticipated target. However, in most situations, the majority of the devices that received the packet were NOT the anticipated targets and thus caused a considerable amount of processing waste. With IPv6 the capabilities that used the IPv4 broadcast address type are replaced by a number of different multicast addresses, for example, FF01::1 is used to speak with all local nodes and FF01::2 is used to speak with all local routers.
Anycast
The IPv6 anycast address type is where IPv4 and IPv6 differ. The anycast address type offers something that was not offered with IPv4 which is the ability to send a packet to the closest device. When using anycast, a group of devices are given the same anycast address; when a source looks to send a packet to that address, the routing protocol will calculate the closest match to the source device and send the traffic there.Summary
While there are some differences between the address types for IPv4 and IPv6, for the most part these differences are easy to understand. One important change is the removal of a broadcast mechanism; this mechanism was commonly abused and caused a great deal of excess overhead on local devices. The idea is that without this ability, devices will be able to spend less time processing those packets that it does not care about and use this time for those that it does. Once IPv6 replaces IPv4 on the majority of devices, these design decisions will be truly proven one way or the other. The content of this article will hopefully help the reader understand the differences between the two IP versions and help in the continuing transition to IPv6.
Tag :
IPv6
The IPv6 Header
The IPv6 Header
As shown in Figure 1, the IPv6 header has been designed to be simple and
easy to process. This enables IPv6 devices the ability to spend the
majority of their time dealing with the data contained within the packet
and not the packet header itself.
Version :
The version field is 4 bits long and is used to tell the processing equipment the version of the IP header that can be expected; when building an IPv6 header the value of the Version field is 6 (0110).Traffic Class :
The Traffic Class field is an 8 bit field that is used to signify the importance of the data contained within this specific packet. With IPv4, this information was signified with the TOS field and supported both IP precedence and Differentiated Services Code Point (DSCP). The Traffic Class field used with IPv6 supports DSCP solely; this specification uses the first 6 bits to indicate the Per Hop Behavior (PHB) of the contained data; these PHB’s are defined in RFC 2474 and its additions.Flow Label :
Before understanding the Flow Label the definition of a flow must be understood. Think of a flow as a stream of traffic that is coming from one source and destined for one or more destinations; a flow will contain multiple packets which can each be treated exactly the same way by intermediate routing devices. The Flow Label is used to identify these flows and enables these intermediate routing devices to treat all of the packets within the flow the same, this reduces processing time and because of this delay.Payload Length :
The Payload Length field is used to indicate the total size of the payload contained within the IPv6 packet. This is then used by the processing devices to ensure that the packet has been completely received. It is important to note that this differs from how the Length field is used with the IPv4 header which contains the length for the whole IPv4 packet.Next Header :
The Next Header field can be used in two different ways depending on the makeup of the specific IPv6 packet. The first is to indicate the protocol that is contained within the packet. The second is a little more complex; IPv6 has the ability to add extension headers after the main IPv6 packet header. These extension headers are used to indicate that the packet has specific options attached to it; this information was contained within the Options (or IP Options) IPv4 header field.Hop Limit :
The Hop Limit field is very simple and replaces the Time to Live (TTL) field that is contained within IPv4 packets. The value that is placed within the field limits the total number of hops that the specific packet is allowed to travel, for example if the value was 2, the packet could only travel a total of 2 additional hops before being discarded.Source Address and Destination Address
The source and destination fields contain the original IPv6 device source address and the original IPv6 destination address. This information is then used by all intermediate devices to route the packet to its expected destination and to return traffic to the original source should a problem occur.Summary
While the IPv6 header is different in its structure from the IPv4 header, its function is exactly the same. Knowledge of the IPv6 header has become mandatory knowledge for most network engineers as the transition to IPv6 is here for many organizations. Hopefully the information contained within this article will help in becoming more familiar with IPv6 and how it operates.
Tag :
IPv6
How to make Windows 7 Bootable USB Pendrive
Windows 7 Bootable USB Pendrive
Many of us face a lot of problem when we have to reinstall windows on our computer or laptop. First thing we have to decide from where to install windows? The options available are DVD or USB Pendrive. In the latest new netbooks, mostly there is no DVD drive. So if you want to install windows you have to go with the other option, i.e. USB Pendrive. So here I give a brief and 100% tested tutorial on how to create a Windows 7 Bootable USB Pendrive to install Windows 7 from USB Pendrive.
First thing, you should check whether your BIOS supports booting from USB. Most of the computer/laptops support. But if your BIOS doesn’t, then sorry, you cannot boot from a USB Pendrive.
Second thing, you need another computer with Windows installed with a DVD drive, to copy its contents later.
So let us start with the procedure now:
1) Run command prompt (cmd). This can be done by clicking start and typing typing cmd in Windows 7. In Windows Xp, click on start and then click on run. Type cmd and run. This will open the command prompt which will look like this:
2) Then run diskpart utility from command prompt, by typing
‘DISKPART’ on command prompt and pressing enter. This will run the
diskpart utility in a separate windows, which is shown in 2nd picture
below:
‘DISK 2′ is our pen drive. Warning: In your computer it may be some other number. In our case it is ‘DISK 2′
5) Then you have to run a series of commands. The commands to be run in the order are:-
-CLEAN
- CREATE PARTITION PRIMARY
- SELECT PARTITION 1
- ACTIVE
- FORMAT FS=FAT32
These steps are shown in the image below:
6) The format step will take some time. You can have a tea or coffee in the meantime and come back. After the format is complete you have to run ‘assign’ command. And after this you can exit diskpart utility by entering the ‘EXIT’ command. The steps are shown below:
- ASSIGN
- EXIT
7) After the format is complete, put in your original Windows 7 DVD in your DVD drive, or if you have an
.iso image of the DVD, mount that image using any virtual drive software like Power ISO.
- Now go to My Computer, and open the contents of DVD Drive. Press ‘ctrl+a’ to select all contents and copy all the contents by pressing ‘ctrl+c’.
- Now go back to My Computer and open the USB Drive and press ‘ctrl+v’ to paste all the contents of DVD into the USB Disk.
Tag :
Tips and Tricks,
Windows
Windows 7 cool shortcuts
Windows 7 cool shortcuts
You all must be very tired of using your mouse, so here are some of the very cool shortcuts using your keyboard on windows 7.
Hope you like all of them.
1) Windows + left arrow OR Windows + right arrow : Dock selected window to the left or right half of your screen.
2) Windows + up arrow OR Windows + down arrow : Maximized and restores the selected window.
3) Windows + Spacebar : Makes all open windows transparent to view gadgets and icons on desktop.
4) Windows + Home : Minimizes all but selected window. Reverse by clicking the key combination again.
5) Windows + Tab : Launch 3D representation of open windows and click Tab key again to flip through them.
6) Windows + T OR Windows + SHIFT + T : Move focus to front or back of taskbar. Press T again while holding the Windows key to cycle through items in the taskbar from left to right or, with SHIFT button held too, from right to left.
7) Windows + 1 THROUGH Windows + 9 : Launch first through ninth icon on taskbar, including items pinned to taskbar.
Windows + SHIFT + 1 THROUGH Windows + SHIFT + 9 : Starts new instance of respective taskbar icon.9) Windows + Ctrl + 1 THROUGH Windows + Ctrl + 9 : Cycles through multiple instances of the respective icon.
10) Windows + Alt + 1 THROUGH Windows + Alt + 9 : Opens jump list for respective icon.
11) Windows + P : Select presentation display mode.
12) Windows + G : Cycle through desktop gadgets.
13) Windows + X : Launches Windows Mobility Center. Most useful if you’re working on a laptop.
Tag :
Tips and Tricks,
Windows